1. Field of the Invention
The present invention is related to a welding bellows capable of absorbing torsion, and in particular to a welding bellows which can absorb torsional displacement with respect to the center axis while maintaining sealability.
2. Description of the Prior Art
Prior art welding bellows have a wave-shaped cross section in the axial direction, wherein the inner diameter and the outer diameter have the same axis so that the wave shape is repeated in a multistage manner. These prior art bellows can absorb expansion and contraction displacement in the axial direction and displacement due to bending, but they can not absorb torsional displacement.
Further, Japanese Laid-Open Patent Publication No. HEI 5-67835 proposes a torsion bellows having a prescribed incline with respect to the center axis of the bellows and a ridgeline shape with continuous alternating peaks and valleys in the axial direction between both ends. However, this torsion bellows can not absorb expansion and contraction displacement in the axial direction and displacement due to bending.
First with respect to ultrahigh vacuum devices, there is a surprisingly high demand to absorb torsional angular displacement with respect to the center axis while maintaining sealability.